Would you accept an organ from a sheep? The Times reports from Tochigi in Japan that these genetically engineered animals could solve the country’s organ donor shortage.

Currently Yutaka Hanazono and team at the Jichi Medical University has only created sheep with organs suitable for chimpanzees. Stem cells extracted from chimps are grown in a sheep to create fully-formed organs such as a spare pancreas. He believes that within a decade or two the technology could be extended to create human organs as well.

“We have made some very big advances here. There has historically been work on the potential of sheep as producers of human blood, but we are only slowly coming closer to the point where we can harvest sheep for human organs,” Professor Hanazono told The Times.

That will be too long for many Japanese patients seeking donors, as the legal system in Japan has created a deficit in organs. Death is defined at the point when the heart stops, at which point organs will begin to degrade from lack of blood flow. Brain death, where all brain activity has ceased but the heart and lungs can be kept functioning, allows more effective harvesting of organs, but Japan does not allow this.

The result is an extremely low rate of donation in Japan. The US has about 27 organ donors per million people, but in Japan this figure is less than 1 donor per million people. This forces many patients to seek organs abroad, but even this “transplant tourism” will become difficult as international rules on organs become more strict.

The Japanese people have a complicated moral choice ahead of them. Either they must revise their laws defining death, or accept the possibility of growing organs on demand. Both options have serious cultural and ethical implications, not just scientific ones, but something must be done to alleviate the organ shortage.